WASHINGTON -- National Rifle Association CEO Wayne LaPierre said Friday that future school shootings like the one in Newtown, Conn., one week ago can only be prevented if schools have armed security guards, just as the Secret Service protects President Obama.

Guns were not to blame for the mass shooting at Sandy Hook Elementary School that killed 20 children and six adults last week, LaPierre said. "The only thing that stops a bad guy with a gun is a good guy with gun," LaPierre said at the news conference that was interrupted twice by anti-gun activists.

"Politicians pass laws for gun-free school zones," LaPierre said. "They issue press releases bragging about them. They post signs advertising them. And in so doing, they tell every insane killer in America that schools are their safest place to inflict maximum mayhem with minimum risk."

The widely anticipated news conference followed a week of relative silence from the NRA, a politically potent voice on behalf of gun rights with 4.3 million members. Those who expected a bold departure from the group's avid pro-gun rights stance were quickly disappointed by LaPierre's comments.

"Instead of offering solutions to a problem they have helped create, they offered a paranoid, dystopian vision of a more dangerous and violent America where everyone is armed and no place is safe," New York Mayor Michael Bloomberg said. "Today the NRA's lobbyists blamed everyone but themselves for the crisis of gun violence...Enough."

LaPierre criticized anti-gun advocates for weakening school safety, the media for perpetuating anti-gun stereotypes and a "shadow industry" of game developers and movie producers for creating a fertile field in which a culture of violence has grown.

He showed a clip from a game called "Kindergarten Killers," which showed small children being shot that he said had been online for 10 years. "Isn't fantasizing about killing people as a way to get your kicks really the filthiest form of pornography?" he asked.

The NRA conference followed a statement from President Obama in which he responded to petitioners calling for more gun control. He asked them for help in forging policies to prevent shooting like Sandy Hook. "I'm asking for your help to make a real meaningful difference in the lives of our communities and our country," Obama said in a video posted on the White House petition website.

In an effort to prevent future tragedies, LaPierre announced the formation of National School Shield Emergency Response Program that would help schools prepare for potential threats. Former representative Asa Hutchinson, R-Ark., will lead that program, LaPierre said.

Hutchinson said the new initiative will employ independent security experts to help school officials, parents and communities craft "a comprehensive strategy for school security" and all them to tailor it to their needs - including armed security personnel.

"School safety is a complex issue with no simple, single solution," he said. "But I believe trained, qualified, armed security is one key component among many that can provide the first line of deterrence as well as the last line of defense."

The press conference at times turned chaotic as protesters from the anti-war group Code Pink chanted anti-gun slogans as they were hauled out of the ballroom of the Willard Hotel by one of the many security guards that stood in and around the event.

After the second protester unfurled a banner, one of the guards sat in a chair in the space where both disturbances occurred.

None of the three speakers, LaPierre, Hutchinson and NRA President David Keene, took questions from reporters, some of whom shouted questions despite Keene's warning that none would be answered until Monday.

LaPierre is scheduled to appear on NBC's Meet the Press on Sunday.

The NRA had remained silent in the aftermath of the shooting at Sandy Hook Elementary, much like the group had following other incidents over the past few years.

That changed on Tuesday, when the group issued a statement announcing the news conference and expressing shock and sadness at the shooting.

LaPierre's comments lived up to the expectations of NRA supporters. Rep. Dan Burton, R-Ind., said Thursday that he hoped the groups would stand firm for the Second Amendment.

"If I were advising them and I'm not, I'd start telling them that we should live up to the Constitution and the Second Amendment. You know, that's it," Burton said. "And if you have somebody that's mentally unbalanced, you are going to have these problems. I don't know how you do away with that."

But officials who have advocated for regulations of firearms joined Bloomberg in blasting LaPierre's comments Friday, calling them disappointing and "shameful."

"I know that the American people - including many gun owners - are heartbroken and fed up with the gun violence we've seen recently at an elementary school, a shopping mall, a temple, a movie theater, a supermarket parking lot, and on countless American streets every single day," Rep. Carolyn McCarthy, D-N.Y., said in a statement.

McCarthy, whose husband was killed in a mass shooting in 1993, is one of several lawmakers who have pledged to introduce measures aimed at reducing gun violence. That includes bills to close loopholes that allow unregulated sales at gun shows, more comprehensive background checks and bans on high-capacity ammunition magazines.

She said she will join Sen. Dianne Feinstein, D-Calif., in reintroducing a new version of the assault weapons ban in January. The previous law passed in 1994 and expired in 2004.

Feinstein said Friday "if school districts want to hire armed security guards, I support that. It's a decision each school district should make."

One third of all public schools, about 28,300, have armed security staff, Feinstein said. But in the 1999 shooting at Columbine High School in Littleton, Colo., the school's armed guards were unable to stop two heavily armed students from killing 12 students and one teacher before killing themselves.

"The NRA's blanket call to arm our schools is really nothing more than a distraction, it's a delay tactic," Feinstein said. "It's a distraction from the availability of military style assault weapons on our streets, in our schools, used at malls, used at work places, used in movie theaters and they allow for much death and destruction."

Mark Kelly, husband of former Rep. Gabrielle Giffords, D-Ariz., who was shot in the head in a January 2011 mass shooting in front of a Tucson grocery store, wrote in a Facebook post that he and Giffords were "extremely disappointed" in the NRA's "defiant and delayed response" to the Connecticut shootings.

"The time for this kind of extreme rhetoric is over," he said. "We must have a real conversation about preventing gun violence, because when it comes to protecting our children, families, and neighbors, we can't wait any longer."